Electric car being charged at EV charge point for electric vehicles at Z service station in Wellington. Photo by Lynn Grieveson.

The Commerce Commission is warning monopoly electricity networks not to treat electric vehicle chargers as assets they can charge all electricity users for.

“The main purpose of EV chargers is to charge cars, not transport electricity," the commission's deputy chair, Sue Begg, said in an open letter on a wider issue that is causing tension between electricity retailers and network owners, both of which see business opportunities emerging from selling new technologies such as rooftop solar units, batteries, EVs and home management systems that use digital technology to revolutionise household and commercial energy management.

"Our starting point is that we do not expect the costs associated with (EV) chargers to be included in their regulated asset bases, as they are not a cost of providing regulated services that consumers ultimately pay for through their power bills,” Begg said in a letter that unregulated electricity retailers are counting as a win in their campaign to prevent monopoly lines network owners from subsidising new technology business with income from their regulated asset bases.

"We need to ensure that consumers benefit from advances in technology, while at the same time promoting the development of competitive energy markets. Regulated monopolies should not have an unfair advantage over existing and future competitors in this space,” the commission said.

The letter "reminds electricity lines companies about how emerging technology costs and revenues should be accounted for in order to comply with their regulatory requirements" and "includes new guidance on when investments in electric vehicle chargers can be included in their regulated asset base, which they can earn a return on from their customers".

Auckland-based network owner Vector has been at the forefront among network owners in positioning itself for the electrification of the national transport fleet, the rise of embedded generation systems, such as rooftop solar and home energy storage through batteries that are starting to become more affordable, and in home automation systems using the so-called "Internet of Things".

The commission now plans to gather information from regulated electricity network owners to gain a better understanding of how they are planning, investing and accounting for such new technologies.

The letter also reminds electricity lines companies about their obligations under the Commerce Act to "ensure they do not enter into agreements which will substantially lessen competition, or take advantage of market power for an anticompetitive purpose in unregulated and competitive energy services markets they are seeking to enter or already participate in".